Jaw crushers typically comprise a fixed jaw and a movable jaw that together define a crushing zone. A drive mechanism is operative to rock the movable jaw back and forth in order to crush material within this zone. The crushing zone is generally convergent towards its lower discharge end so that crushable material, fed to an upper and wider end of the zone, is capable of falling downward under gravity whilst being subject to repeated cycles of crushing movement in response to the cyclical motion of the movable jaw. The crushed material is then discharged under gravity through the lower and narrower discharge end onto a conveyor for onward processing or a stockpiling.
Commonly, the frame that supports the fixed jaw is referred to as the front frame end and the movable jaw is connected to what is typically referred to as a back-frame-end via a mechanically actuated link mechanism that serves to control and stabilise the oscillating movement of the movable jaw relative to the stationary jaw. Typically, the link mechanism is both statically and dynamically linearly adjustable to control the grade or size of the resultant crushed material and to facilitate absorption of the impact forces generated by the crushing action.
As will be appreciated, the mechanically actuated link mechanism typically comprises a toggle assembly having a toggle plate that may be positionally supported by wedges, shims or powered cylinders. The toggle assembly is typically held under axial compression when supporting the movable jaw by a retraction or tension assembly mounted to a lower region of the movable jaw and the back-frame-end. Example jaw crushers comprising linkage assemblies to support the movable jaw are described in U.S. Pat. No. 5,799,888; EP 1190722 and U.S. Pat. No. 6,375,105.
However, conventional retraction assemblies are disadvantageous for a number of reasons. In particular, the pivot mountings of the retraction rods and the cylinder are subject to accelerated wear due to the continued transmission of loading forces and torque. Additionally, the combined axial length of existing linkage assemblies is often difficult to accommodate within the limited space available at the lower, rear region of the crusher which creates problems when it is required to mount the crusher within confined spaces. Accordingly, what is required is jaw mounting assembly that addresses these problems.